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-rw-r--r--xpcom/threads/nsThreadSyncDispatch.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/xpcom/threads/nsThreadSyncDispatch.h b/xpcom/threads/nsThreadSyncDispatch.h
new file mode 100644
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--- /dev/null
+++ b/xpcom/threads/nsThreadSyncDispatch.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsThreadSyncDispatch_h_
+#define nsThreadSyncDispatch_h_
+
+#include "nsThreadUtils.h"
+#include "LeakRefPtr.h"
+#include "mozilla/DebugOnly.h"
+
+class nsThreadSyncDispatch : public mozilla::Runnable
+{
+public:
+ nsThreadSyncDispatch(nsIThread* aOrigin, already_AddRefed<nsIRunnable>&& aTask)
+ : mOrigin(aOrigin)
+ , mSyncTask(mozilla::Move(aTask))
+ {
+ }
+
+ bool IsPending()
+ {
+ return !!mSyncTask;
+ }
+
+private:
+ NS_IMETHOD Run() override
+ {
+ if (nsIRunnable* task = mSyncTask.get()) {
+ mozilla::DebugOnly<nsresult> result = task->Run();
+ MOZ_ASSERT(NS_SUCCEEDED(result),
+ "task in sync dispatch should not fail");
+ // We must release the task here to ensure that when the original
+ // thread is unblocked, this task has been released.
+ mSyncTask.release();
+ // unblock the origin thread
+ mOrigin->Dispatch(this, NS_DISPATCH_NORMAL);
+ }
+ return NS_OK;
+ }
+
+ nsCOMPtr<nsIThread> mOrigin;
+ // The task is leaked by default when Run() is not called, because
+ // otherwise we may release it in an incorrect thread.
+ mozilla::LeakRefPtr<nsIRunnable> mSyncTask;
+};
+
+#endif // nsThreadSyncDispatch_h_